History – Named after Adolph Kussmaul (1822-1902), a German physician, who noticed it in patients with severe diabetes mellitus and first published the finding in 1874. Dr. Kussmaul was a prolific physician in the late 1880’s and this is just one of many eponymous distinctions that bears his name. I am sure his name will come again in this series.

What are 3 pretest probability scoring systems used to evaluate patients with a suspected pulmonary thromboembolism?

Answer

There are 3 validated pretest probability scoring systems that can be used to help clinicians decide who can be sent home, who needs a D-dimer, and who goes straight to CT for suspected PTE.

Wells Criteria

Developed – 1998

Revised – 2000

Simplified – 2001

Geneva Score

Developed – 2001

Revised – 2006

Simplified – 2008

Pulmonary Embolism Rule-Out Criteria (PERC) Score

Developed – 2008

This score is used AFTER the patient is determined to be low-risk using the Well’s or Geneva score. In patients who are low-risk and PERC negative, there is only a 1.6% false-negative rate for missed PTE. Any one of these would deem the patient PERC positive.

Why is this so important?

Although it does help us in deciding who maybe at higher risk of PTE, I personally feel these scoring systems help us document who DOES NOT need work-up. There are quite a few patients who come in with non-specific chest pain or shortness of breath, and you should ALWAYS entertain the idea of PTE in these patients. But, not every single one of these patients need a d-dimer or CTA. Better yet, some of these patients can be discharged home without any investigation if they are low-risk and PERC negative.

Below is an algorithm I modified from Jeff Kline using these clinical decision instruments.

This is actually a special episode for the PAINE Podcast as I have the opportunity to do a joint-interview podcast with Chip Lange from TOTAL EM. This was the first time I got to dabble with a conversational-style podcast and I think it went pretty good. Chip and I had a great time doing it and will most definitely be doing more of these in the future.

One of the many saying my Army Airborne Ranger dad has instilled in me growing (and one that I still use today) is the seven “P” approach to accomplishing tasks:

Proper

Planning

and

Preparation

Prevents

Piss

Poor

Performance

What is nice about this saying is that it applies very nicely to the steps of intubation as well.

Prepare

You need to to have everything at the bedside you MIGHT need prior to any intubation attempt. This includes equipment, medications, and any personnel or team members who will assist. If you even suspect this could be a difficult airway, you should have your plan B and plan C options in the room to ward off the evil spirits.

Endotracheal tubes (3 sizes), stylets, bougies, syringes

Test the balloons on all the tubes

Laryngoscope

Multiple blades and handles

Check the lights

If using video, plug it in and make sure it turns on

Patent IV lines x 2

Suction

Cardiac and pulse oximetry monitor

Bag-valve mask

End-tidal CO2 monitor

Medications

Drawn up and labeled

Concentration read aloud

This also gives you the opportunity to talk with you team about the plan for intubation (how many attempts, progression should plan A, steps of what will happen during the intubation and everyone’s roles during the procedure, etc..), as well as reviewing assisting maneuvers (external laryngeal manipulation, etc.).

Preoxygenate

In order to decrease any deoxygenation-related issues during the intubation attempt, your patient should recieve 100% oxygen at 15 liters per minute through a non-rebreather mask for 3-5 minutes. This will properly de-nitrogenate and super-saturate all the hemoglobin and give you the time you need to visualize and intubate.

Position

“EAR HOLE TO CHEST HOLE”

For ideal visualization, you want to position your patient so that their external auditory meatus lined up to the sternal notch

Premedicate

There are several different medications you can give for premedication purposes to modify the physiologic response during intubation (lidocaine, opiates, atropine, defasculating agents, etc..), but the main one is the sedative. It is generally poor form to paralyze someone before you sedate them. There are several medications you can choose from for sedation in intubation:

Ketamine – 1-2mg/kg IV

My ideal sedative

Etomidate 0.3mg/kg IV

Less hemodynamic compromise

Can cause adrenal suppression

Propofol – 1.5-3mg/kg IV

Can cause hemodynamic instability

Paralyze

There are 2 choices for classes of paralytics:

Depolarizing

Succinylcholine – 1.5-2mg/kg IV

Rapid onset, shortest duration of action

Caution in burn/crush injuries, hyperkalemic patients

Non-Depolarizing

Rocuronium – 1.2mg/kg IV

Vecuronium – 0.3mg/kg IV

Pass The Tube

Once you patient is properly sedative and paralyze, you can proceed to laryngoscopy.

Post-intubation Assessment

Capnography

This is used for confirmation of correct placement of the endotracheal in the trachea and tests for end-tidal CO2. There are 2 main types:

Qualitative

Color change calorimeter

Attaches to end of endotracheal tube and detects CO2 by changes in exhaled pH

GOLD IS GOOD

Quantitative

Continuous Waveform Capnography

Gold standard

Gives you a visual waveform to see if the ventilations are adequate

Securing the Tube

Once you know you are in the right spot and have been confirmed by capnography, you need to secure the tube. There are different ways to achieve and I often defer to the respiratory therapist or nurse on how they want it secured. There are commercial devices that lock the tube in place and secure using velcro straps, all the way to the old standby of adhesive tape. This is a great site that shows several different ways you can secure the endotracheal tube (http://aam.ucsf.edu/article/securing-endotracheal-tube).

Radiography

Chest xray is the gold standard for the radiographical confirmation of endotracheal placement, as well as ensuring the proper depth. The ideal position for the tube depth should be 3-5cm from the carina or at T3-4 position.

Now that the tube is in place, secured, and confirmed, you are done right? WRONG!!! Your patient now has a tube shoved into the tracheal and it is a tad uncomfortable. Postintubation sedation/analgesia is PARAMOUNT for good patient care.

Sedation

Ketamine – 0.1-0.5mg/kg bolus and 0.1-0.5mg/kg/hr infusion

Propofol – 5mcg/kg bolus and 5-50mcg/kg/hr infusion

Midazolam – 0.05mg/kg bolus and 0.025mg/kg/hr infusion

Analgesia

Fentanyl – 2mcg/kg bolus and 1mcg/kg/hr infusion

Hydromorphone – 0.5-1mg/kg bolus and 0.5-3mg/kg/hr infusion

Morphine – 5-10mg/kg bolus and 2-30mg/hr infusion

You should be shooting for a Richmond Agitation Sedation Scale (RASS) of -1 to -3 for adequate sedation following intubation.

Epidemiology

Dyspnea is one of the more common complaints that will bring a patient to the ED for evaluation. The most recent data from the CDC shows more than 3.7 million visits to the ED in the United States for shortness of breath alone and more than 11 million for dyspnea-related complaints (cough, chest pain, etc.).

Pathophysiology

There are 3 global processes that have to function in series to prevent a patient from becoming short of breath:

Ventilation

Airflow through the tracheobronchial tree to the terminal alveoli

Ventilation without perfusion = Dead space

Anatomic = trachea, main bronchi

Physiologic = terminal alveoli

Perfusion

Blood flow through the pulmonary arteries to the terminal capillaries

Perfusion without ventilation = Intrapulmonary shunt

Anatomic = right-to-left shunt

Physiologic = terminal alveoli

Gas Exchange

Capillary-alveoli interface to exchange oxygen and carbon dioxide

Determined by arterial-alveoli gradient

5 Main Causes of Hypoxemia

V/Q Mismatch (most common)

PNA, PTE, pulmonary edema, asthma, COPD

Hypoventilation

Drug overdose, neuromuscular disease (GBS, ALS, MG)

Right-to-Left Shunt

Intracardiac

PFO, ASD, VSD

Vascular

PTE, AVM

Alveolar

PNA, atelectasis, pulmonary edema, ARDS

Low Inspired Oxygen

Altitude, fire,

Diffusion Abnormality

COPD, interstitial lung disease

Bedside Evaluation

Vitals

Blood Pressure

Often hypertensive due to stress

Can also be the precipitating factor

Heart Rate

Often tachycardic due to stress and system trying to increase cardiac output for oxygen demand

If bradycardic à think overdose

Respiratory Rate

Will be tachypnic

> 40 bpm is ominous and respiratory failure could be imminent

if bradypnic à think overdose

Temperature

If febrile, then infectious causes go up on differential

Pulse oximetry

Common practice is to give all dyspneic patients oxygen

Lots of research on oxygen in ACS

History

Onset

Severity

Events leading up to this episode

Triggers, compliance with medications

Allergies

Past History

Medical problems, previous episodes

Chest pain

Trauma

Fever

Hemoptysis

Cough

Tobacco history

Medications

Physical Exam

Rapid examination should be performed (often while getting the history) to evaluate for impending respiratory collapse:

Altered mental status

Lethargy to combative

Fatigue of breathing

Audible stridor

Cyanosis

Tripod position

Retractions or accessory muscle use

Fragmented speech

Inability to lie supine

Diaphoresis

Any of the above findings should raise your threshold to intubate.

Once these have been evaluated and ruled-out, you can begin a focused physical exam to address the causes of acute dyspnea:

As with any educational or academic en devour, as soon as you finish a paper/poster/presentation, a new publication comes out that would have been awesome to include. I finished and published the Pneumonia podcast on July 12th and on July 14th, the IDSA/ATS released their updated guidelines on managing healthcare-associated (HAP) and ventilator-associated (VAP) pneumonia. Luckily, they didn’t change anything earth-shattering, just tightened them up a bit. Antibiotic regimens are below and they recommend 7-days total of therapy.

Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia. American journal of respiratory and critical care medicine. 171(4):388-416. 2005. [pubmed]